I had to call my utility to get this information, and it applies specifically to the Springtree water treatment plant in Sunrise, FL for Broward County. I don't know if you can use this as an approx for other near by cities, as I do know that Sunrise manages the water for a few of the western muncipalities. Here is what I got:

Ca hardness as CaCO_3 = 30ppm

Total hardness as CaCo_3 = 40 - 130 ppm annual average

Alkalinity as CaCO_3 = 20 ppm or greater (last week was 48ppm)

Chloride = 250 ppm or less... not to helpful here

Sodium = 44 ppm

With this information, and using Palmer's guide, I gather the following:

Calcium = 12 ppm

Magnesium = 13.31 ppm

Bicarbonates = 39.34 ppm

Sulfate = ? Not sure on this

Sodium = 44 ppm

Chloride <= 250 ppm

Perhaps this may help folks out there looking for an approximate number, Cheers!

What concerns me about this water is the fairly large spread for actual measurements. This may be because your city can draw from a number of different sources depending on the demand and availability of water. While the water quality report indicates that they draw mainly from the Biscayne Aquifer, in the neat picture in the water quality report they also indicate access to the Floridian Aquifer.

I suggest that you get a GH&KH test kit and keep track of changes in your water's hardness and alkalinity. You may also want to talk to your water department about what seasonal changes you can expect. A tds meter may also be handy since it reads much quicker than a GH&KH test and you can test the water once you see a difference in TDS.

Another option is to get an R/O filter, take out most of the minerals and start from a now more stable water profile.